Repetitive control for pneumatic anti-vibration apparatuses under a multi-loop control system

This paper considers the compensation of both flow disturbance and floor vibration for pneumatic anti-vibration apparatuses (AVAs). To compensate for effects of the flow disturbance, repetitive control is employed. When the tunable parameter of a repetitive controller is high gain, the flow disturbance is further suppressed. On the other hand, transmissibility increases. To overcome the trade-off between the flow disturbance suppression and the transmissibility reduction, the setting method of the tunable parameter is presented. In the case of single-loop control system, the transmissibility decreases by using a notch filter as the tunable parameter, whereas in the case of a multi-loop control system, the transmissibility increases at a certain frequency. To avoid this issue, an inverse notch filter is selected as the tunable parameter. It is shown that the transmissibility can be improved by using the inverse notch and notch filters as the tunable parameter.